A coating and developing apparatus for coating a resist to a substrate and developing the substrate after exposure is used as an apparatus for forming a resist pattern on a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal display (LCD). A heat treating apparatus called bake apparatus is employed in the coating and developing apparatus. For example, an apparatus for heating a substrate coated with a liquid resist takes a role in drying a solvent in the liquid resist.
An example of such a heat treating apparatus 100 is shown in FIG. 13. The heat treating apparatus 100 is divided into an upper chamber 102 and a lower chamber 103 which are partitioned by a bottom plate 101. A cooling plate 104 and a heat treating section 105 are installed in the upper chamber 102 and lifting mechanisms 106 and 107 of wafers are installed in the lower chamber 103. The cooling plate 104 can be moved by a drive mechanism (not shown) between a position (home position) shown in the Figure and an upper position of a heating plate 108 provided in the heat treating section 105. That is, if a substrate, e.g. a wafer, which is transferred from a transfer port 109 into the upper chamber 102 by a transfer mechanism (not shown), is mounted on the cooling plate disposed in the home position by the lifting mechanism 106, it is moved to the upside of the heating plate 108 by the cooling plate 104 and is mounted on the heating plate 108 via the lifting mechanism 107.
Then, after the cooling plate 104 is returned to the home position, the wafer is heat-treated on the heating plate 108. Further, during the heat treatment, supply of a gas and exhaustion of a volatile material are performed with respect to the wafer by a gas supply unit 113 and an exhaustion unit 114 via a gas supply pipe 111 and an exhaustion pipe 112 which are connected to an upper cover 110. Further, the cooling plate 104 is moved to the upside of the heating plate 108 and the wafer is received from the heating plate 108 to the cooling plate 104 via the lifting mechanism 107. Then, the wafer is returned to the home position and a rough cooling is performed to the wafer.
In the case in which the heat treating apparatus 100 is embedded in the coating and developing apparatus, the wafer is conveyed from the upper chamber 102 to a cooling plate for precise control of temperature by a conveyer mechanism (not shown) so that the temperature of the wafer can be precisely controlled. As mentioned above, since the time required for performing cooling in the cooling plate for precise control of temperature is shortened by performing cooling with the cooling plate 104 provided in the heat treating apparatus 100, the number of cooling plates for precise control of temperature, which are required for the coating and developing apparatus can be reduced, thereby scaling down the coating and developing apparatus.
On the other hand, in the conventional heat treating apparatus, the wafer mounted onto the cooling plate is cooled by flowing a cooling liquid in a cooling pipe provided in the interior of or at a lower portion of the cooling plate, which complicates the structure of the cooling plate and increase the size of the heat treating apparatus.
In order to solve the problem and to simplify the overall structure of a heat treating apparatus, for example, Japanese Patent Laid-open application No. 2001-230172 discloses a technology in which heat pipes are provided in the a cooling plate instead of a cooling pipe to cooling the cooling plate through the heat pipes. A plurality of lines of heat pipes are installed in the interior of the cooling plate. The heat pipes absorbs the heat of a wafer mounted onto the cooling plate and discharges the heat to a cooling medium such as a cooling water flowing in a heat exchanging unit installed adjacent to the cooling plate. The cooling medium is supplied from a cooling medium source to the heat exchanging unit via a supply pipe. Then, the heat is absorbed from the heat pipes by the heat exchanging unit and is discharged to a discharge passage via a discharge pipe.
In the case of maintaining or exchanging the cooling plate or the heat treating apparatus set, since there is a need to separate a heat treating apparatus from the coating and developing apparatus, it is necessary to separate a supply pipe and a discharge pipe from the cooling plate. Then, since a cooling medium remains in the heat exchanging unit, the cooling medium drops when the supply pipe and the discharge pipe are separated from the cooling plate, thereby causing troubles in an electrical system of the coating and developing apparatus and producing particles on a wafer. Therefore, in the case in which the supply pipe and the discharge pipe are separated from the cooling plate, a gas is supplied into the pipe to discharge the cooling medium in the pipe, which is time-consuming.